;
|
;
|
; intrpt.s -- a first attempt to utilize interrupts
|
; intrpt.s -- a first attempt to utilize interrupts
|
;
|
;
|
|
|
.set stack,0xC0010000 ; stack
|
.set stack,0xC0010000 ; stack
|
.set timerbase,0xF0000000 ; timer base address
|
.set timerbase,0xF0000000 ; timer base address
|
.set termbase,0xF0300000 ; terminal base address
|
.set termbase,0xF0300000 ; terminal base address
|
|
|
reset:
|
reset:
|
j start ; reset arrives here
|
j start ; reset arrives here
|
|
|
intrpt:
|
intrpt:
|
j isr ; interrupts arrive here
|
j isr ; interrupts arrive here
|
|
|
userMiss:
|
userMiss:
|
j userMiss ; user TLB miss exceptions arrive here
|
j userMiss ; user TLB miss exceptions arrive here
|
|
|
isr:
|
isr:
|
mvfs $26,0 ; determine cause
|
mvfs $26,0 ; determine cause
|
slr $26,$26,14 ; $26 = 4 * IRQ number
|
slr $26,$26,14 ; $26 = 4 * IRQ number
|
and $26,$26,0x1F << 2
|
and $26,$26,0x1F << 2
|
ldw $26,$26,irqsrv ; get addr of service routine
|
ldw $26,$26,irqsrv ; get addr of service routine
|
jr $26 ; jump to service routine
|
jr $26 ; jump to service routine
|
|
|
start:
|
start:
|
add $29,$0,stack ; set sp
|
add $29,$0,stack ; set sp
|
add $4,$0,runmsg ; pointer to string
|
add $4,$0,runmsg ; pointer to string
|
jal msg ; show string
|
jal msg ; show string
|
add $8,$0,timerbase ; program timer
|
add $8,$0,timerbase ; program timer
|
add $9,$0,1000 ; divisor = 1000
|
add $9,$0,1000 ; divisor = 1000
|
stw $9,$8,4
|
stw $9,$8,4
|
add $9,$0,2 ; enable timer interrupts
|
add $9,$0,2 ; enable timer interrupts
|
stw $9,$8,0
|
stw $9,$8,0
|
mvfs $8,0
|
mvfs $8,0
|
or $8,$8,1 << 14 ; open timer IRQ mask bit
|
or $8,$8,1 << 14 ; open timer IRQ mask bit
|
or $8,$8,1 << 23 ; enable processor interrupts
|
or $8,$8,1 << 23 ; enable processor interrupts
|
or $8,$8,1 << 27 ; let vector point to RAM
|
or $8,$8,1 << 27 ; let vector point to RAM
|
mvts $8,0
|
mvts $8,0
|
start1:
|
start1:
|
j start1 ; loop
|
j start1 ; loop
|
|
|
tmrisr:
|
tmrisr:
|
add $8,$0,0x02 ; ien = 1, int = 0
|
add $8,$0,0x02 ; ien = 1, int = 0
|
stw $8,$0,timerbase
|
stw $8,$0,timerbase
|
j shmsg
|
j shmsg
|
|
|
shmsg:
|
shmsg:
|
mvfs $8,0
|
mvfs $8,0
|
slr $8,$8,14 ; $8 = 4 * IRQ number
|
slr $8,$8,14 ; $8 = 4 * IRQ number
|
and $8,$8,0x1F << 2
|
and $8,$8,0x1F << 2
|
ldw $4,$8,msgtbl ; get addr of message
|
ldw $4,$8,msgtbl ; get addr of message
|
jal msg ; show message
|
jal msg ; show message
|
rfx ; return from exception
|
rfx ; return from exception
|
|
|
msg:
|
msg:
|
sub $29,$29,8 ; save registers
|
sub $29,$29,8 ; save registers
|
stw $31,$29,4
|
stw $31,$29,4
|
stw $16,$29,0
|
stw $16,$29,0
|
add $16,$4,$0 ; get pointer
|
add $16,$4,$0 ; get pointer
|
msg1:
|
msg1:
|
ldbu $4,$16,0 ; get char
|
ldbu $4,$16,0 ; get char
|
beq $4,$0,msg2 ; null - finished
|
beq $4,$0,msg2 ; null - finished
|
jal out ; output char
|
jal out ; output char
|
add $16,$16,1 ; bump pointer
|
add $16,$16,1 ; bump pointer
|
j msg1 ; next char
|
j msg1 ; next char
|
msg2:
|
msg2:
|
ldw $16,$29,0 ; restore registers
|
ldw $16,$29,0 ; restore registers
|
ldw $31,$29,4
|
ldw $31,$29,4
|
add $29,$29,8
|
add $29,$29,8
|
jr $31 ; return
|
jr $31 ; return
|
|
|
out:
|
out:
|
add $8,$0,termbase ; set I/O base address
|
add $8,$0,termbase ; set I/O base address
|
out1:
|
out1:
|
ldw $9,$8,8 ; get status
|
ldw $9,$8,8 ; get status
|
and $9,$9,1 ; xmtr ready?
|
and $9,$9,1 ; xmtr ready?
|
beq $9,$0,out1 ; no - wait
|
beq $9,$0,out1 ; no - wait
|
stw $4,$8,12 ; send char
|
stw $4,$8,12 ; send char
|
jr $31 ; return
|
jr $31 ; return
|
|
|
; service routine table
|
; service routine table
|
|
|
irqsrv:
|
irqsrv:
|
.word shmsg ; 00: terminal 0 transmitter interrupt
|
.word shmsg ; 00: terminal 0 transmitter interrupt
|
.word shmsg ; 01: terminal 0 receiver interrupt
|
.word shmsg ; 01: terminal 0 receiver interrupt
|
.word shmsg ; 02: terminal 1 transmitter interrupt
|
.word shmsg ; 02: terminal 1 transmitter interrupt
|
.word shmsg ; 03: terminal 1 receiver interrupt
|
.word shmsg ; 03: terminal 1 receiver interrupt
|
.word shmsg ; 04: keyboard interrupt
|
.word shmsg ; 04: keyboard interrupt
|
.word shmsg ; 05: unused
|
.word shmsg ; 05: unused
|
.word shmsg ; 06: unused
|
.word shmsg ; 06: unused
|
.word shmsg ; 07: unused
|
.word shmsg ; 07: unused
|
.word shmsg ; 08: disk interrupt
|
.word shmsg ; 08: disk interrupt
|
.word shmsg ; 09: unused
|
.word shmsg ; 09: unused
|
.word shmsg ; 10: unused
|
.word shmsg ; 10: unused
|
.word shmsg ; 11: unused
|
.word shmsg ; 11: unused
|
.word shmsg ; 12: unused
|
.word shmsg ; 12: unused
|
.word shmsg ; 13: unused
|
.word shmsg ; 13: unused
|
.word tmrisr ; 14: timer interrupt
|
.word tmrisr ; 14: timer interrupt
|
.word shmsg ; 15: unused
|
.word shmsg ; 15: unused
|
.word shmsg ; 16: bus timeout exception
|
.word shmsg ; 16: bus timeout exception
|
.word shmsg ; 17: illegal instruction exception
|
.word shmsg ; 17: illegal instruction exception
|
.word shmsg ; 18: privileged instruction exception
|
.word shmsg ; 18: privileged instruction exception
|
.word shmsg ; 19: divide instruction exception
|
.word shmsg ; 19: divide instruction exception
|
.word shmsg ; 20: trap instruction exception
|
.word shmsg ; 20: trap instruction exception
|
.word shmsg ; 21: TLB miss exception
|
.word shmsg ; 21: TLB miss exception
|
.word shmsg ; 22: TLB write exception
|
.word shmsg ; 22: TLB write exception
|
.word shmsg ; 23: TLB invalid exception
|
.word shmsg ; 23: TLB invalid exception
|
.word shmsg ; 24: illegal address exception
|
.word shmsg ; 24: illegal address exception
|
.word shmsg ; 25: privileged address exception
|
.word shmsg ; 25: privileged address exception
|
.word shmsg ; 26: unused
|
.word shmsg ; 26: unused
|
.word shmsg ; 27: unused
|
.word shmsg ; 27: unused
|
.word shmsg ; 28: unused
|
.word shmsg ; 28: unused
|
.word shmsg ; 29: unused
|
.word shmsg ; 29: unused
|
.word shmsg ; 30: unused
|
.word shmsg ; 30: unused
|
.word shmsg ; 31: unused
|
.word shmsg ; 31: unused
|
|
|
; message table
|
; message table
|
|
|
msgtbl:
|
msgtbl:
|
.word xmtmsg ; 00: terminal 0 transmitter interrupt
|
.word xmtmsg ; 00: terminal 0 transmitter interrupt
|
.word rcvmsg ; 01: terminal 0 receiver interrupt
|
.word rcvmsg ; 01: terminal 0 receiver interrupt
|
.word xmtmsg ; 02: terminal 1 transmitter interrupt
|
.word xmtmsg ; 02: terminal 1 transmitter interrupt
|
.word rcvmsg ; 03: terminal 1 receiver interrupt
|
.word rcvmsg ; 03: terminal 1 receiver interrupt
|
.word kbdmsg ; 04: keyboard interrupt
|
.word kbdmsg ; 04: keyboard interrupt
|
.word uimsg ; 05: unused
|
.word uimsg ; 05: unused
|
.word uimsg ; 06: unused
|
.word uimsg ; 06: unused
|
.word uimsg ; 07: unused
|
.word uimsg ; 07: unused
|
.word dskmsg ; 08: disk interrupt
|
.word dskmsg ; 08: disk interrupt
|
.word uimsg ; 09: unused
|
.word uimsg ; 09: unused
|
.word uimsg ; 10: unused
|
.word uimsg ; 10: unused
|
.word uimsg ; 11: unused
|
.word uimsg ; 11: unused
|
.word uimsg ; 12: unused
|
.word uimsg ; 12: unused
|
.word uimsg ; 13: unused
|
.word uimsg ; 13: unused
|
.word tmrmsg ; 14: timer interrupt
|
.word tmrmsg ; 14: timer interrupt
|
.word uimsg ; 15: unused
|
.word uimsg ; 15: unused
|
.word btmsg ; 16: bus timeout exception
|
.word btmsg ; 16: bus timeout exception
|
.word iimsg ; 17: illegal instruction exception
|
.word iimsg ; 17: illegal instruction exception
|
.word pimsg ; 18: privileged instruction exception
|
.word pimsg ; 18: privileged instruction exception
|
.word dimsg ; 19: divide instruction exception
|
.word dimsg ; 19: divide instruction exception
|
.word timsg ; 20: trap instruction exception
|
.word timsg ; 20: trap instruction exception
|
.word msmsg ; 21: TLB miss exception
|
.word msmsg ; 21: TLB miss exception
|
.word wrmsg ; 22: TLB write exception
|
.word wrmsg ; 22: TLB write exception
|
.word ivmsg ; 23: TLB invalid exception
|
.word ivmsg ; 23: TLB invalid exception
|
.word iamsg ; 24: illegal address exception
|
.word iamsg ; 24: illegal address exception
|
.word pamsg ; 25: privileged address exception
|
.word pamsg ; 25: privileged address exception
|
.word uemsg ; 26: unused
|
.word uemsg ; 26: unused
|
.word uemsg ; 27: unused
|
.word uemsg ; 27: unused
|
.word uemsg ; 28: unused
|
.word uemsg ; 28: unused
|
.word uemsg ; 29: unused
|
.word uemsg ; 29: unused
|
.word uemsg ; 30: unused
|
.word uemsg ; 30: unused
|
.word uemsg ; 31: unused
|
.word uemsg ; 31: unused
|
|
|
; sign-on message
|
; sign-on message
|
|
|
runmsg:
|
runmsg:
|
.byte "system running..."
|
.byte "system running..."
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
; interrupt messages
|
; interrupt messages
|
|
|
uimsg:
|
uimsg:
|
.byte "unknown interrupt"
|
.byte "unknown interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
xmtmsg:
|
xmtmsg:
|
.byte "terminal transmitter interrupt"
|
.byte "terminal transmitter interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
rcvmsg:
|
rcvmsg:
|
.byte "terminal receiver interrupt"
|
.byte "terminal receiver interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
kbdmsg:
|
kbdmsg:
|
.byte "keyboard interrupt"
|
.byte "keyboard interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
dskmsg:
|
dskmsg:
|
.byte "disk interrupt"
|
.byte "disk interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
tmrmsg:
|
tmrmsg:
|
.byte "timer interrupt"
|
.byte "timer interrupt"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
; exception messages
|
; exception messages
|
|
|
uemsg:
|
uemsg:
|
.byte "unknown exception"
|
.byte "unknown exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
btmsg:
|
btmsg:
|
.byte "bus timeout exception"
|
.byte "bus timeout exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
iimsg:
|
iimsg:
|
.byte "illegal instruction exception"
|
.byte "illegal instruction exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
pimsg:
|
pimsg:
|
.byte "privileged instruction exception"
|
.byte "privileged instruction exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
dimsg:
|
dimsg:
|
.byte "divide instruction exception"
|
.byte "divide instruction exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
timsg:
|
timsg:
|
.byte "trap instruction exception"
|
.byte "trap instruction exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
msmsg:
|
msmsg:
|
.byte "TLB miss exception"
|
.byte "TLB miss exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
wrmsg:
|
wrmsg:
|
.byte "TLB write exception"
|
.byte "TLB write exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
ivmsg:
|
ivmsg:
|
.byte "TLB invalid exception"
|
.byte "TLB invalid exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
iamsg:
|
iamsg:
|
.byte "illegal address exception"
|
.byte "illegal address exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
pamsg:
|
pamsg:
|
.byte "privileged address exception"
|
.byte "privileged address exception"
|
.byte 0x0D, 0x0A, 0
|
.byte 0x0D, 0x0A, 0
|
|
|
